// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2012 Freescale Semiconductor, Inc.
 *
 * Copyright (C) 2014 Linaro.
 * Viresh Kumar <viresh.kumar@linaro.org>
 */

#include <linux/clk.h>
#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/cpumask.h>
#include <linux/err.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/pm_opp.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
#include <linux/thermal.h>

#include "cpufreq-dt.h"
#ifdef CONFIG_ARCH_ROCKCHIP
#include "rockchip-cpufreq.h"
#endif

struct private_data {
    struct list_head node;

    cpumask_var_t cpus;
    struct device *cpu_dev;
    struct opp_table *opp_table;
    struct cpufreq_frequency_table *freq_table;
    bool have_static_opps;
};

static LIST_HEAD(priv_list);

static struct freq_attr *cpufreq_dt_attr[] = {
    &cpufreq_freq_attr_scaling_available_freqs,
    NULL, /* Extra space for boost-attr if required */
    NULL,
};

static struct private_data *cpufreq_dt_find_data(int cpu)
{
    struct private_data *priv;

    list_for_each_entry(priv, &priv_list, node)
    {
        if (cpumask_test_cpu(cpu, priv->cpus)) {
            return priv;
        }
    }

    return NULL;
}

static int set_target(struct cpufreq_policy *policy, unsigned int index)
{
    struct private_data *priv = policy->driver_data;
    unsigned long freq = policy->freq_table[index].frequency;

#ifdef CONFIG_ARCH_ROCKCHIP
    return rockchip_cpufreq_opp_set_rate(priv->cpu_dev, freq * 0x3e8);
#else
    return dev_pm_opp_set_rate(priv->cpu_dev, freq * 0x3e8);
#endif
}

/*
 * An earlier version of opp-v1 bindings used to name the regulator
 * "cpu0-supply", we still need to handle that for backwards compatibility.
 */
static const char *find_supply_name(struct device *dev)
{
    struct device_node *np;
    struct property *pp;
    int cpu = dev->id;
    const char *name = NULL;

    np = of_node_get(dev->of_node);
    /* This must be valid for sure */
    if (WARN_ON(!np)) {
        return NULL;
    }

    /* Try "cpu0" for older DTs */
    if (!cpu) {
        pp = of_find_property(np, "cpu0-supply", NULL);
        if (pp) {
            name = "cpu0";
            goto node_put;
        }
    }

    pp = of_find_property(np, "cpu-supply", NULL);
    if (pp) {
        name = "cpu";
        goto node_put;
    }

    dev_dbg(dev, "no regulator for cpu%d\n", cpu);
node_put:
    of_node_put(np);
    return name;
}

static int cpufreq_init(struct cpufreq_policy *policy)
{
    struct private_data *priv;
    struct device *cpu_dev;
    struct clk *cpu_clk;
    unsigned int transition_latency;
    int ret;

    priv = cpufreq_dt_find_data(policy->cpu);
    if (!priv) {
        pr_err("failed to find data for cpu%d\n", policy->cpu);
        return -ENODEV;
    }
    cpu_dev = priv->cpu_dev;

    cpu_clk = clk_get(cpu_dev, NULL);
    if (IS_ERR(cpu_clk)) {
        ret = PTR_ERR(cpu_clk);
        dev_err(cpu_dev, "%s: failed to get clk: %d\n", __func__, ret);
        return ret;
    }

    transition_latency = dev_pm_opp_get_max_transition_latency(cpu_dev);
    if (!transition_latency) {
        transition_latency = CPUFREQ_ETERNAL;
    }

    cpumask_copy(policy->cpus, priv->cpus);
    policy->driver_data = priv;
    policy->clk = cpu_clk;
    policy->freq_table = priv->freq_table;
    policy->suspend_freq = dev_pm_opp_get_suspend_opp_freq(cpu_dev) / 0x3e8;
    policy->cpuinfo.transition_latency = transition_latency;
    policy->dvfs_possible_from_any_cpu = true;

    /* Support turbo/boost mode */
    if (policy_has_boost_freq(policy)) {
        /* This gets disabled by core on driver unregister */
        ret = cpufreq_enable_boost_support();
        if (ret) {
            goto out_clk_put;
        }
        cpufreq_dt_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs;
    }

    dev_pm_opp_of_register_em(cpu_dev, policy->cpus);

    return 0;

out_clk_put:
    clk_put(cpu_clk);

    return ret;
}

static int cpufreq_online(struct cpufreq_policy *policy)
{
    /* We did light-weight tear down earlier, nothing to do here */
    return 0;
}

static int cpufreq_offline(struct cpufreq_policy *policy)
{
    /*
     * Preserve policy->driver_data and don't free resources on light-weight
     * tear down.
     */
    return 0;
}

static int cpufreq_exit(struct cpufreq_policy *policy)
{
    clk_put(policy->clk);
    return 0;
}

static struct cpufreq_driver dt_cpufreq_driver = {
    .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK | CPUFREQ_IS_COOLING_DEV,
    .verify = cpufreq_generic_frequency_table_verify,
    .target_index = set_target,
    .get = cpufreq_generic_get,
    .init = cpufreq_init,
    .exit = cpufreq_exit,
    .online = cpufreq_online,
    .offline = cpufreq_offline,
    .name = "cpufreq-dt",
    .attr = cpufreq_dt_attr,
    .suspend = cpufreq_generic_suspend,
};

static int dt_cpufreq_early_init(struct device *dev, int cpu)
{
    struct private_data *priv;
    struct device *cpu_dev;
    bool fallback = false;
    const char *reg_name;
    int ret;

    /* Check if this CPU is already covered by some other policy */
    if (cpufreq_dt_find_data(cpu)) {
        return 0;
    }

    cpu_dev = get_cpu_device(cpu);
    if (!cpu_dev) {
        return -EPROBE_DEFER;
    }

    priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
    if (!priv) {
        return -ENOMEM;
    }

    if (!alloc_cpumask_var(&priv->cpus, GFP_KERNEL)) {
        return -ENOMEM;
    }

    cpumask_set_cpu(cpu, priv->cpus);
    priv->cpu_dev = cpu_dev;

    /*
     * OPP layer will be taking care of regulators now, but it needs to know
     * the name of the regulator first.
     */
    reg_name = find_supply_name(cpu_dev);
    if (reg_name) {
        priv->opp_table = dev_pm_opp_set_regulators(cpu_dev, &reg_name, 1);
        if (IS_ERR(priv->opp_table)) {
            ret = PTR_ERR(priv->opp_table);
            if (ret != -EPROBE_DEFER) {
                dev_err(cpu_dev, "failed to set regulators: %d\n", ret);
            }
            goto free_cpumask;
        }
    }

    /* Get OPP-sharing information from "operating-points-v2" bindings */
    ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, priv->cpus);
    if (ret) {
        if (ret != -ENOENT) {
            goto out;
        }

        /*
         * operating-points-v2 not supported, fallback to all CPUs share
         * OPP for backward compatibility if the platform hasn't set
         * sharing CPUs.
         */
        if (dev_pm_opp_get_sharing_cpus(cpu_dev, priv->cpus)) {
            fallback = true;
        }
    }

    /*
     * Initialize OPP tables for all priv->cpus. They will be shared by
     * all CPUs which have marked their CPUs shared with OPP bindings.
     *
     * For platforms not using operating-points-v2 bindings, we do this
     * before updating priv->cpus. Otherwise, we will end up creating
     * duplicate OPPs for the CPUs.
     *
     * OPPs might be populated at runtime, don't check for error here.
     */
    if (!dev_pm_opp_of_cpumask_add_table(priv->cpus)) {
        priv->have_static_opps = true;
    }

    /*
     * The OPP table must be initialized, statically or dynamically, by this
     * point.
     */
    ret = dev_pm_opp_get_opp_count(cpu_dev);
    if (ret <= 0) {
        dev_err(cpu_dev, "OPP table can't be empty\n");
        ret = -ENODEV;
        goto out;
    }

    if (fallback) {
        cpumask_setall(priv->cpus);
        ret = dev_pm_opp_set_sharing_cpus(cpu_dev, priv->cpus);
        if (ret) {
            dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n", __func__, ret);
        }
    }

#ifdef CONFIG_ARCH_ROCKCHIP
    rockchip_cpufreq_adjust_power_scale(cpu_dev);
#endif

    ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &priv->freq_table);
    if (ret) {
        dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
        goto out;
    }

    list_add(&priv->node, &priv_list);
    return 0;

out:
    if (priv->have_static_opps) {
        dev_pm_opp_of_cpumask_remove_table(priv->cpus);
    }
    if (priv->opp_table) {
        dev_pm_opp_put_regulators(priv->opp_table);
    }
free_cpumask:
    free_cpumask_var(priv->cpus);
    return ret;
}

static void dt_cpufreq_release(void)
{
    struct private_data *priv, *tmp;

    list_for_each_entry_safe(priv, tmp, &priv_list, node)
    {
        dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &priv->freq_table);
        if (priv->have_static_opps) {
            dev_pm_opp_of_cpumask_remove_table(priv->cpus);
        }
        if (priv->opp_table) {
            dev_pm_opp_put_regulators(priv->opp_table);
        }
        free_cpumask_var(priv->cpus);
        list_del(&priv->node);
    }
}

static int dt_cpufreq_probe(struct platform_device *pdev)
{
    struct cpufreq_dt_platform_data *data = dev_get_platdata(&pdev->dev);
    int ret, cpu;

    /* Request resources early so we can return in case of -EPROBE_DEFER */
    for_each_possible_cpu(cpu)
    {
        ret = dt_cpufreq_early_init(&pdev->dev, cpu);
        if (ret) {
            goto err;
        }
    }

    if (data) {
        if (data->have_governor_per_policy) {
            dt_cpufreq_driver.flags |= CPUFREQ_HAVE_GOVERNOR_PER_POLICY;
        }

        dt_cpufreq_driver.resume = data->resume;
        if (data->suspend) {
            dt_cpufreq_driver.suspend = data->suspend;
        }
        if (data->get_intermediate) {
            dt_cpufreq_driver.target_intermediate = data->target_intermediate;
            dt_cpufreq_driver.get_intermediate = data->get_intermediate;
        }
    }

    ret = cpufreq_register_driver(&dt_cpufreq_driver);
    if (ret) {
        dev_err(&pdev->dev, "failed register driver: %d\n", ret);
        goto err;
    }

    return 0;
err:
    dt_cpufreq_release();
    return ret;
}

static int dt_cpufreq_remove(struct platform_device *pdev)
{
    cpufreq_unregister_driver(&dt_cpufreq_driver);
    dt_cpufreq_release();
    return 0;
}

static struct platform_driver dt_cpufreq_platdrv = {
    .driver =
        {
            .name = "cpufreq-dt",
        },
    .probe = dt_cpufreq_probe,
    .remove = dt_cpufreq_remove,
};
module_platform_driver(dt_cpufreq_platdrv);

MODULE_ALIAS("platform:cpufreq-dt");
MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
MODULE_DESCRIPTION("Generic cpufreq driver");
MODULE_LICENSE("GPL");
